Electric bicycle safety control method based on NFC starting and electric bicycle

Abstract

The invention relates to the technical field of NFC, electric bicycle intelligent control and the like, and provides an electric bicycle safety control method based on NFC starting and an electric bicycle. The vehicle is provided with a master control MCU, an instrument, an NFC card, a power supply, a vehicle lamp switch module and a motor; and when the NFC card is close to the instrument, the instrument completes identity verification and sends a starting request to the MCU, and the MCU synchronously starts the BMS, the vehicle lamp and the motor. The BMS firstly bidirectionally shakes hands with the charger and the battery module, allows charging and discharging after confirming that the charger and the battery module are original, monitors parameters such as voltage, current and temperature in real time, and dynamically limits current according to a preset multi-parameter algorithm; if it is detected that the positive and negative electrodes of the battery are reversely connected or collided to cause transient large current, a charge-discharge path is cut off. According to the method, identity safety power-on, mutual recognition of original components, continuous soft current limiting and millisecond-level short circuit protection are achieved, and the safety, reliability and anti-theft performance of the whole life cycle of the whole vehicle are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical fields of NFC, intelligent control of electric bicycles, and the like, and in particular to an electric bicycle safety control method based on NFC starting and an electric bicycle. BACKGROUND

[0002] Most existing electric bicycles use mechanical keys or simple buttons as power-on starting methods, lack fast electronic verification of the identity of the rider, and have security risks of vehicle theft or illegal starting of the vehicle by others. In addition, although the whole vehicle battery management system (BMS) has basic overvoltage, undervoltage, overcurrent and overtemperature protection, it still has the following shortcomings: the existing BMS usually only monitors the voltage level, and even if it is connected to a non-original charger or a battery module that is compatible but lacks sufficient safety level, it will still allow charging and discharging, resulting in mismatched charging parameters, abnormal internal resistance temperature rise or lithium dendrite risk. Moreover, the existing BMS commonly uses fixed current profiles or stepwise current limiting methods, and lacks comprehensive judgment of the combination of voltage, temperature and current, which is prone to two extremes of power deficiency caused by excessive current limiting or damage to the battery cell caused by response lag. In terms of short circuit protection, the existing solutions mostly rely on single-point Hall or fuse-type hardware short circuit protection, which is slow in detecting transient reverse connection or short-time high-current impact caused by battery component collision during plugging and unplugging, and the protection action often occurs after the fault has been formed. In addition, the whole vehicle electronic system of the existing electric bicycle is isolated from each other, and the instrument, the vehicle light and the motor controller are dispersed, and the power-on logic is not deeply linked with the BMS, so it cannot realize linkage control in the complete link of identity confirmation, whole vehicle power-on, battery safety verification.

[0003] In summary, the industry urgently needs a whole safety control method based on identity security starting, original component mutual recognition, real-time dynamic current limiting and fine-grained abnormality detection to improve the safety and reliability of electric bicycles throughout their entire life cycle. SUMMARY

[0004] In view of the shortcomings of the prior art, the present application provides an electric bicycle safety control method based on NFC starting and an electric bicycle, which realizes identity security starting, original component mutual recognition, real-time dynamic current limiting and fine-grained abnormality detection, and improves the safety and reliability of electric bicycles throughout their entire life cycle.

[0005] In a first aspect, the present application provides an electric bicycle safety control method based on NFC starting, comprising:

[0006] The electric bicycle is equipped with a main control MCU, an instrument, an NFC card, a power supply, a lamp switch module and a motor, when the NFC card approaches the instrument, the instrument identifies the NFC card as valid, and sends a start request to the main control MCU, after the main control MCU receives the start request, sends a start signal to the BMS, the lamp switch module and the motor of the electric bicycle, so that the BMS starts to prepare for charging and discharging;

[0007] After the BMS receives the start signal, it performs handshake authentication with the charger and the battery module respectively, and after confirming that the handshake with the charger and the battery module is successful, it is determined that the charger and the battery module are original, and the battery module is allowed to perform normal charging and discharging; the BMS monitors the charging and discharging state of the battery module when allowing the charging and discharging operation, and dynamically adjusts the charging and discharging current according to the parameters of the real-time monitored charging and discharging state, the parameters of the charging and discharging state including voltage, current and temperature parameters; when dynamically adjusting the charging and discharging current, the BMS adjusts the charging and discharging current according to the parameters of the real-time monitored charging and discharging state by using a preset algorithm;

[0008] During the charging and discharging process, the BMS detects the positive and negative connection state and the positive and negative collision state of the battery module in real time, and when detecting that the battery module appears positive and negative reverse connection or positive and negative collision, the BMS controls the battery module to stop charging and discharging.

[0009] In the second aspect, the application provides an electric bicycle controlled by the above-mentioned electric bicycle safety control method based on NFC start.

[0010] Compared with the prior art, the application has the following beneficial effects:

[0011] The application provides a kind of electric bicycle safety control method based on NFC start and electric bicycle, electric bicycle is equipped with main control MCU, instrument, NFC card, power supply, car light switch module and motor, when NFC card approaches instrument, instrument identifies that NFC card is effective, and sends start request to main control MCU, after main control MCU receives start request, sends start signal to BMS of electric bicycle, car light switch module and motor, so that BMS starts to carry out charge-discharge preparation;BMS receives start signal, and carries out handshake authentication with charger and battery module respectively, after confirming that the handshake with charger and battery module is all successful, it is judged that charger and battery module are all original, and battery module is allowed to carry out normal charge-discharge;The BMS monitors the charge-discharge state of battery module when allowing charge-discharge operation, and dynamically adjusts charge-discharge current according to the parameter of the charge-discharge state monitored in real time, and the parameter of the charge-discharge state includes voltage, current and temperature parameter;When dynamically adjusting charge-discharge current, the BMS adjusts charge-discharge current using preset algorithm according to the parameter of the charge-discharge state monitored in real time;During charge-discharge process, BMS detects the positive and negative connection state and positive and negative collision state of battery module in real time, when detecting that battery module appears positive and negative reverse connection or positive and negative collision, BMS controls battery module to stop charge-discharge. BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings, which are incorporated in and constitute a part of this application, several embodiments of the application are illustrated by way of example and not limitation, as follows:

[0013] Fig. 1 It is a kind of flow schematic diagram of the electric bicycle safety control method based on NFC start of the embodiment of the application;

[0014] Fig. 2 It is a kind of circuit structure schematic diagram of NFC high-frequency receiving circuit of the embodiment of the application. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0016] See also Figs. 1-2 This embodiment provides an electric bicycle safety control method based on NFC startup, including the following steps:

[0017] S101: The electric bicycle is equipped with a main control MCU, an instrument, an NFC card, a power supply, a light switch module, and a motor. When the NFC card is brought close to the instrument, the instrument recognizes that the NFC card is valid and sends a start request to the main control MCU. After receiving the start request, the main control MCU sends a start signal to the electric bicycle's BMS, light switch module, and motor, causing the BMS to begin preparing for charging and discharging.

[0018] S102: After receiving the start signal, the BMS performs handshake authentication with the charger and the battery module respectively. After confirming that the handshake with the charger and the battery module is successful, it determines that the charger and the battery module are both original and allows the battery module to charge and discharge normally. When allowing the charge and discharge operation, the BMS monitors the charge and discharge status of the battery module and dynamically adjusts the charge and discharge current according to the parameters of the charge and discharge status monitored in real time, and the parameters of the charge and discharge status include voltage, current and temperature parameters. When dynamically adjusting the charge and discharge current, the BMS adjusts the charge and discharge current according to the parameters of the charge and discharge status monitored in real time using a preset algorithm.

[0019] S103. During the charging and discharging process, the BMS detects the positive and negative pole connection status and the positive and negative pole collision status of the battery module in real time. When it is detected that the positive and negative poles of the battery module are reversely connected or the positive and negative poles collide, the BMS controls the battery module to stop charging and discharging.

[0020] It should be noted that in the embodiment, the NFC electronic authentication is used to replace the mechanical key, the rider identity verification can be completed in a short distance, and the probability of vehicle theft or misoperation by others is greatly reduced. The main control MCU synchronously unlocks the BMS, the vehicle light and the motor in the same control link after the identity verification is successful, so as to realize the cooperative control of identity, power-on and power, and compared with the traditional power-on scheme of each module, the safety hidden danger of battery output or motor idling without authentication is avoided. In addition, in the embodiment, the two-way handshake not only increases the dynamic token verification once compared with the one-way ID verification, but also advances the authentication to before the current is allowed to flow, so that the overvoltage, overcurrent and compatibility risks caused by the use of non-original charger or battery are fundamentally eliminated, and the probability of thermal runaway event triggered by component mismatch is greatly reduced. In addition, in the embodiment, the voltage, temperature and current are coupled into the same preset algorithm in real time, so as to avoid the dilemma between excessive power reduction in slight abnormality and response lag in severe abnormality caused by fixed gear or step-type current limiting, improve the battery pack capacity retention rate, reduce the MOS channel resistance drift, and prolong the life of the battery cell and power device. In addition, in the embodiment, the BMS detects the positive and negative connection state and the positive and negative collision state of the battery module in real time. When it is detected that the battery module is in positive and negative reverse connection or positive and negative collision, the BMS controls the battery module to stop charging and discharging, realizes two-stage protection from soft current limiting to hard cutting, realizes impact energy release reduction, and prevents secondary damage such as battery cell welding point melting and wire ablation. Moreover, since the MCU grasps the overall state, the vehicle light and power can be synchronously turned off and reported to the instrument when a fault occurs, so as to avoid the user continuing to discharge at high load after losing power.

[0021] Further, when the preset algorithm is used to regulate the charging and discharging current, the BMS calculates the real-time allowed charging and discharging current value I set according to the real-time monitored voltage, current and temperature parameters through the following formula.

[0022]

[0023] In the formula, I nom represents the rated charging and discharging current of the battery module; K v is a voltage regulation coefficient, and its calculation formula is as follows.

[0024]

[0025] In the formula, V bat is the real-time voltage of the battery; V nom is the rated voltage of the battery module, and a v is a voltage regulation sensitivity coefficient; K i is a current regulation coefficient, and its calculation formula is as follows.

[0026]

[0027] In the formula, Ibat is the real-time current of the battery, and a is the current regulation sensitivity coefficient; i is the real-time current of the battery, and a is the current regulation sensitivity coefficient;

[0028] K t is the temperature regulation coefficient, and the calculation formula is:

[0029]

[0030] wherein, T bat is the real-time temperature of the battery, T opt is the optimal working temperature of the battery, T max and T min are the maximum and minimum values of the working temperature of the battery, respectively, a is the temperature regulation sensitivity coefficient; t is the real-time current of the battery, and a is the current regulation sensitivity coefficient;

[0031] The BMS compares the calculated real-time allowed charging and discharging current value I set with the current actual current of the battery module, and outputs a regulation signal to control the MOS tube driving circuit to dynamically adjust the actual charging and discharging current of the battery module.

[0032] It should be noted that in the embodiment, the allowed current is calculated in real time by the product coupling of the voltage coefficient, the current coefficient and the temperature coefficient. The three coefficients are dynamically combined, and when a single parameter deviates slightly from the rated value, the reduction amplitude is diluted by another parameter to maintain normal output. When multiple parameters deviate simultaneously, the product effect will quickly drop, thereby completing the gradual current limiting within milliseconds. In addition, the fixed coefficient of the existing BMS cannot simultaneously consider different battery chemistries (NCA, NCM, lithium iron phosphate, etc.) and use scenarios (high-cold regions, steep slope large current climbing, summer high-temperature commuting). In the embodiment, through the adjustable sensitivity coefficients a v , a i , a t , the lithium-iron battery which is sensitive to cycle life can be set to a t larger value, the temperature slightly increases and the current decreases, the high-rate NCM can be set to a i lower value, and the discharge rate is fully utilized. In the high-cold strategy package, a v is increased to offset the voltage drop caused by the increase in internal resistance at low temperature, and in the city commuting strategy package, a v is reduced to improve the power response when stopping and starting frequently, thereby improving the energy utilization efficiency under different vehicle models, different regions and different user use scenarios. In addition, I set = I nom × K v × K i × K tThe MOS gate drive takes a PWM duty ratio continuous smooth adjustment instead of ON / OFF two-state switching, avoiding the MOS thermal shock and cell electrochemical stress caused by large current change of the hard current limiting.

[0033] Preferably, the instrument identifying the NFC card specifically includes: the NFC chip built-in the instrument receiving the near field communication signal sent by the NFC card through the NFC high-frequency receiving circuit, analyzing the unique identification data of the near field communication signal sent by the NFC card, and judging whether the unique identification data is consistent with the preset data in the memory to verify the validity of the NFC card. It should be noted that in the present embodiment, the electronic authentication of the user's identity is realized by analyzing the unique identification data sent by the NFC card and comparing it with the preset data (such as a preset key table or a white list), which has higher anti-copying and anti-tampering capabilities compared with traditional mechanical keys or unencrypted key starts. It should be noted that in conventional NFC applications, it is common to trigger a simple wake-up signal, and the unique identification comparison mechanism in the present embodiment is more secure than the weak logic of the conventional card responding to the proximity. It can be understood that by matching the unique identification data with the pre-stored data list in the memory, multiple NFC cards corresponding to different users, permissions or use scenarios (such as maintenance, rental, management) can be supported, providing flexible control capabilities. It should be further pointed out that in the present embodiment, the verification action is not a local response in isolation, but provides a trusted identity confirmation signal source for the whole vehicle system (MCU, BMS, motor, etc.), forming a system solution from physical access to digital verification to vehicle authorization, realizing a safe closed loop from the perception layer to the control layer.

[0034] Further, the NFC high-frequency receiving circuit comprises: a transmitting side inductive resonance unit, a π-type filter and parallel resonance network, a radio frequency signal input and receiving processing unit, and a receiving signal coupling and demodulation path unit; the transmitting side inductive resonance unit comprises a first inductor L2 and a second inductor L3 connected to the TX1 pin and the TX2 pin of the NFC chip respectively, one end of L2 and L3 is connected to the corresponding TX pin respectively, and the other end is connected to the output end of the π-type filter network, for forming a differential high-frequency resonance channel and providing primary impedance matching of the radio frequency transmitting path; the π-type filter and parallel resonance network comprises a capacitor C6, a capacitor C7, a capacitor C8, a capacitor C12, a capacitor C13, and a capacitor C42; one end of the capacitor C6 and the capacitor C7 is connected to the input end of the first inductor L2 as the output end of the π-type filter network, the other end of the capacitor C6 is connected to one end of the capacitor C8 and the output end of the radio frequency signal input and receiving processing unit, the other end of the capacitor C7 and the capacitor C8 is grounded, one end of the capacitor C12 and the capacitor C42 is connected to the input end of the second inductor L3 as the output end of the π-type filter network, the other end of the capacitor C42 is connected to one end of the capacitor C13 and the output end of the radio frequency signal input and receiving processing unit, the other end of the capacitor C12 and the capacitor C13 is grounded; the radio frequency signal input and receiving processing unit comprises an ANT receiving antenna, a current limiting resistor R39 and a current limiting resistor R41 connected in series with the ANT receiving antenna interface, and a coupling capacitor C11 and a coupling capacitor C14, the other end of the current limiting resistor R39 and the current limiting resistor R41 is the output end of the radio frequency signal input and receiving processing unit, the near field communication signal received by the ANT receiving antenna forms a ground coupling path through the capacitor C11 and the capacitor C14 after current limiting by the current limiting resistor R39 and the current limiting resistor R41; the receiving signal coupling and demodulation path unit comprises a capacitor C9, a capacitor C10, a current limiting resistor R42, a current limiting resistor R43, and a capacitor C15, one end of the capacitor C9 is connected to one end of the capacitor C42 and the input end of the second inductor L3, the other end of the capacitor C9 is connected to one end of the capacitor C10 and the current limiting resistor R43, the other end of the capacitor C10 is connected to the current limiting resistor R41, the capacitor C14, and the capacitor C42, the other end of the current limiting resistor R43 is connected to the NFC_RX pin of the NFC chip and one end of the current limiting resistor R42, the other end of the current limiting resistor R42 is connected to the VMID pin of the NFC chip and one end of the capacitor C15, the other end of the capacitor C15 is grounded.

[0035] It should be noted that the transmitting side inductive resonance unit is provided with a first inductor L2 and a second inductor L3 connected to the TX1 pin and the TX2 pin of the NFC chip respectively, a resonance loop is formed through the differential inductive path, a high-Q resonance channel is formed with the pi-type filter, the signal can be accurately tuned to the 13.56 MHz standard NFC frequency band, the maximum gain of the signal in the frequency domain is obtained, the frequency drift and impedance mismatch problems in the single-ended coupling reception are solved, and the technical effects of frequency point locking and accurate control of the transmission passband are realized. In the pi-type filter and parallel resonance network, the capacitors C6, C7, C8, C12, C13 and C42 form differential filter networks in a bidirectional symmetrical structure, and form a multi-stage parallel resonance channel with inductors, wherein the capacitors C6 and C8 are connected to the output end of the radio frequency signal input unit, C7 is connected to the ground, the capacitors C42 and C13 are connected to another branch, C12 is connected to the ground, and a multi-stage coupling and bandpass resonance is formed, which effectively filters out high-frequency interference and low-frequency noise other than NFC signals, ensures that the reception channel only has high permeability to the target frequency band, and improves the signal-to-noise ratio and the front-end anti-interference capability. In the radio frequency signal input and reception processing unit, the near field communication signal received by the ANT receiving antenna is limited by the current limiting resistors R39 and R41, and then forms a ground coupling path through the capacitors C11 and C14, respectively. This structure shares the radio frequency energy through the double-branch series current limiting and coupling capacitor method, while avoiding the risk of burning the front-end coupling capacitor, and improving the fault tolerance of the ANT receiving antenna reception front end. The double-branch input of the ANT receiving antenna is coupled by the R / C network and introduced into the later-stage parallel resonance network, improving the near-field coupling efficiency and signal extraction integrity. In the reception signal coupling and demodulation path unit, one end of the capacitor C9 is connected to the input end of the second inductor L3, the other end is connected to the capacitor C10 and the current limiting resistor R43, and then connected to the NFC_RX pin, the current limiting resistor R42 is connected to the VMID pin and grounded through the capacitor C15, thereby building a differential input path for demodulation. The current limiting resistor controls the radio frequency current amplitude, the capacitor network realizes signal differential coupling, and the VMID provides a reference potential, so that the entire circuit ensures that the signal entering the NFC_RX pin has a stable level and a suitable amplitude range, and guarantees the identification and decision accuracy of the later-stage digital demodulation module.

[0036] Preferably, the NFC chip built-in the instrument communicates with the master MCU through a serial port, and after the instrument verifies the validity of the NFC card, it sends a data packet containing the NFC card state information to the master MCU in a serial port mode to ensure that the master MCU can accurately and timely receive the verification information. It should be noted that in this embodiment, structured state data packets (such as UID, verification result, timestamp, etc.) are transmitted through serial communication instead of GPIO interrupts or analog signal transmission, which can greatly reduce the problem of false triggering caused by signal interference, misreading or timing problems, and improve the reliability of decision-making. In addition, the instrument as a NFC decoding processing unit, separates the identity judgment task from the master MCU, and only issues the result through serial communication, which simplifies the master load and enhances the system modularity. If the master fails, the instrument can independently refuse to respond, and if the instrument communication is abnormal, the master will not start the vehicle, which has good anti-exception ability in complex use scenarios such as shared electric bicycles and remote OTA updates.

[0037] Preferably, the handshake authentication between the BMS and the charger and the battery module specifically includes: after the BMS sends a handshake request data packet, it receives a response data packet from the charger and the battery module, and checks the authentication information in the response data packet to determine whether the charger and the battery module are original equipment. It should be noted that after the BMS sends a handshake request data packet, it receives a response data packet from the charger and the battery module, and checks the authentication information in the response data packet to determine whether the charger and the battery module are original equipment, thereby establishing a two-way authentication process of the BMS to external power supply and energy storage devices, effectively solving the problem of electric bicycles unable to identify non-original components, avoiding battery parameter mismatch, temperature abnormalities or safety loss of control caused by non-standard equipment connection, and improving electrical safety level.

[0038] Preferably, the authentication information in the response data packet includes a pre-stored device unique identification code and a real-time generated handshake token, and the BMS determines whether the charger and the battery module are original equipment according to whether the device unique identification code and the handshake token match the internal preset data. It should be noted that the authentication information in the response data packet includes a pre-stored device unique identification code and a real-time generated handshake token, and the BMS determines whether the charger and the battery module are original equipment according to whether the device unique identification code and the handshake token match the internal preset data, thereby providing a static ID and dynamic token dual verification mechanism in the handshake process, enhancing the anti-counterfeiting and anti-man-in-the-middle attack ability, solving the problem of easy imitation or tampering by matching only static addresses or communication protocol fields, having higher information security and authentication strength, and realizing the reliability improvement of device mutual authentication and the enhancement of system attack resistance.

[0039] Preferably, when the BMS detects the connection state of the positive and negative poles of the battery module in real time, the detection circuit inside the BMS monitors the voltage polarity of the positive and negative poles of the battery module, and when the voltage polarity does not match the preset correct polarity, the BMS controls the battery module to stop charging and discharging. It should be noted that when the voltage polarity of the positive and negative poles of the battery module does not match the preset correct polarity, the BMS controls the battery module to stop charging and discharging, thereby determining in real time at the hardware level whether the battery connection state has a reverse connection error, solving the problem of relying on manual inspection or delayed response when the battery is connected in reverse. When the user plugs in or replaces the battery interface, millisecond-level identification and current path blocking are achieved, effectively preventing MOS overcurrent burnout, battery internal damage, and other safety hazards caused by polarity errors, and improving the robustness of the system to human errors.

[0040] Preferably, the detection circuit for voltage polarity includes a high-voltage detection module and an MCU control unit, the high-voltage detection module monitors the voltage of the positive and negative poles of the battery module in real time, and sends the voltage to the MCU control unit for polarity logic judgment after analog-to-digital conversion. It should be noted that the detection circuit for voltage polarity includes a high-voltage detection module and an MCU control unit, the high-voltage detection module monitors the voltage of the positive and negative poles of the battery module in real time, and sends the voltage to the MCU control unit for polarity logic judgment after analog-to-digital conversion, thereby building a soft and hard cooperative polarity recognition mechanism. By separating high-voltage sampling and logic judgment, the accuracy of polarity judgment is improved, and the judgment threshold can be dynamically set according to the voltage fluctuation trend to effectively deal with boundary conditions such as poor contact and temperature difference drift, and more reliable reverse connection protection and system self-recovery capability are achieved.

[0041] Preferably, when the BMS detects the collision state of the positive and negative poles of the battery module in real time, the BMS uses the built-in short-circuit current detection circuit to monitor the transient current change of the battery module in real time. When the sudden change of the transient current of the battery module is detected to exceed the preset threshold, it is determined that the positive and negative poles of the battery module have collided, and the BMS controls the battery module to stop charging and discharging.

[0042] Preferably, when the master MCU sends a start signal to the vehicle lamp switch module and the motor, the master MCU outputs the start signal to the vehicle lamp switch module and the motor controller through the digital signal control line, the vehicle lamp switch module automatically lights up the vehicle lamp after receiving the start signal, and the motor controller releases the motor locking state after receiving the start signal. It should be noted that the master MCU outputs the start signal to the vehicle lamp switch module and the motor controller through the digital signal control line, the vehicle lamp switch module automatically lights up the vehicle lamp after receiving the start signal, and the motor controller releases the motor locking state, thereby establishing a vehicle subsystem synchronous enabling mechanism based on the NFC authentication result driving, ensuring that the start signal source is authenticated and traceable, preventing the motor or vehicle lamp from being forcibly activated in an illegal state, enhancing the standardization of the control chain and the rationality of the power distribution, and improving the safety guarantee of the vehicle consistency start.

[0043] Preferably, the data communication between the master MCU and the instrument adopts a bidirectional handshaking mechanism, and after the instrument sends a start request to the master MCU, the master MCU returns confirmation information to ensure that the start request is effectively received and prevent communication packet loss or misoperation; in the bidirectional handshaking mechanism, the confirmation information adopts a check bit for data packet integrity check, and after the master MCU sends the confirmation information, the instrument receives the confirmation information and checks the check bit. It should be noted that in this embodiment, the data interaction safety and consistency between the instrument and the master are enhanced through reliable handshaking and redundant verification mechanism, and the misjudgment problem of card swiping failure but power-on misoperation is solved. The check bit can be used to verify the validity of the data packet content, prevent control abnormalities caused by communication interruption, interference or packet error, and at the same time has a state feedback mechanism to ensure that the system has transaction confirmation and link fault tolerance function at the communication layer, and improve the overall system stability and user experience.

[0044] Further, the BMS dynamically controls the current path between the battery module and the load or the charger through the charge and discharge protection control circuit unit when controlling the charge and discharge of the battery module, and the charge and discharge protection control circuit unit comprises:

[0045] a field effect transistor control unit selectively turned on or turned off in response to the charge and discharge control signal of the BMS;

[0046] a gate drive and clamping protection unit electrically connected with the field effect transistor control unit, for adjusting the turn-on or turn-off speed of the field effect transistor control unit, and limiting the gate voltage of the field effect transistor control unit within a safe voltage range;

[0047] a real-time power and energy monitoring unit for real-time acquisition of the voltage value U(t) and the current value I(t) of the battery module, calculation of the real-time discharge power P(t) and the discharge energy cumulative value E(t):

[0048] P(t) = U(t) * I(t),

[0049] In the formula, P(τ) represents the instantaneous power of the battery module at time τ, dτ represents a small time interval, and is used for integral accumulation of energy;

[0050] The safety protection determination unit is configured to calculate a safety risk index S(t) according to the real-time power P(t) and the accumulated discharge energy E(t);

[0051]

[0052] In the formula, P max is the maximum discharge power, E rated is the rated discharge energy of the battery module, T(t) is a real-time temperature, T norm is a normal working temperature of the battery module, and α, β, and γ are preset weight coefficients satisfying the condition α+β+γ=1.

[0053] The safety protection determination unit performs the following actions according to the value range of the safety risk index S(t):

[0054] When S(t)≤S safe , the field effect tube control unit is continuously turned on to allow normal charging and discharging.

[0055] When S safe <S(t)<S crit , the gate drive unit is adjusted to reduce the conduction degree of the field effect tube control unit to reduce the current.

[0056] When S(t)≥S crit , the charging and discharging control signal is immediately revoked, and the field effect tube control unit is turned off, so as to quickly cut off the charging and discharging path of the battery module.

[0057] It should be noted that in the present embodiment, the BMS calculates the real-time discharge power and the discharge energy accumulation value through the real-time power and energy monitoring unit, and calculates the risk index according to the power, the energy, and the temperature. Not only is the basic monitoring of the charging and discharging state realized, but also the energy integral and the exponential temperature increment function are provided to solve the technical problems of slow response to battery risks and difficulty in comprehensive evaluation of the safety of the discharge process in the prior art. Through integral energy monitoring and an exponential temperature risk increment model (such as ), thereby achieving dual perception of long-time discharge heat accumulation and instantaneous high-power abnormality of the battery, and improving sensitivity and accuracy of the safety response. Meanwhile, the safety protection determination unit performs grading protection actions such as continuous conduction, current reduction, or shutdown according to the value range of the calculated safety risk index, realizes dynamic grading intervention, and is adaptable to actual operation conditions such as multiple scenes, long periods, and high loads. Overall, the embodiment constructs a complete discharge protection control strategy from monitoring to response through composite algorithms such as power integration, energy criterion, and multi-dimensional weighted index function, and cooperates with the protection execution mechanism at the circuit level, thereby significantly improving the real-time safety protection capability of the BMS in complex use environments.

[0058] It should be noted that the above embodiments are only preferred specific embodiments of the present application, and the protection scope of the present application is not limited thereto. Any changes or replacements within the technical range disclosed by the present application can be easily thought of by those skilled in the art, and should be covered within the protection scope of the present application, and the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A safety control method for an electric bicycle based on NFC startup, characterized in that: include: The electric bicycle is equipped with a main control MCU, instrument, NFC card, power supply, light switch module and motor. When the NFC card is close to the instrument, the instrument recognizes that the NFC card is valid and sends a start request to the main control MCU. After receiving the start request, the main control MCU sends a start signal to the electric bicycle's BMS, light switch module and motor, so that the BMS begins to prepare for charging and discharging. After receiving the start signal, the BMS performs handshake authentication with the charger and the battery module respectively. After confirming that the handshake with the charger and the battery module is successful, it determines that the charger and the battery module are both original and allows the battery module to charge and discharge normally. When allowing the charge and discharge operation, the BMS monitors the charge and discharge status of the battery module and dynamically adjusts the charge and discharge current according to the parameters of the charge and discharge status monitored in real time, and the parameters of the charge and discharge status include voltage, current and temperature parameters. When dynamically adjusting the charge and discharge current, the BMS uses a preset algorithm to adjust the charge and discharge current according to the parameters of the charge and discharge status monitored in real time. During the charging and discharging process, the BMS detects the positive and negative pole connection status and the positive and negative pole collision status of the battery module in real time. When it detects that the positive and negative poles of the battery module are reversed or the positive and negative poles collide, the BMS controls the battery module to stop charging and discharging.

2. The electric bicycle safety control method based on NFC startup according to claim 1 is characterized in that: The instrument's recognition of the NFC card specifically includes: the instrument's built-in NFC chip receives the near-field communication signal sent by the NFC card through the NFC high-frequency receiving circuit, parses the unique identification data of the near-field communication signal sent by the NFC card, and determines whether the unique identification data is consistent with the preset data in the memory to verify the validity of the NFC card.

3. The electric bicycle safety control method based on NFC startup according to claim 2 is characterized in that: The instrument's built-in NFC chip communicates data with the main control MCU via the serial port. After the instrument verifies the validity of the NFC card, it sends a data packet containing the NFC card status information to the main control MCU via the serial port to ensure that the main control MCU can receive the verification information accurately and promptly.

4. The electric bicycle safety control method based on NFC startup according to claim 1 is characterized in that: The handshake authentication between the BMS and the charger and battery module specifically includes: after the BMS sends a handshake request data packet, it receives a response data packet from the charger and battery module, and verifies the authentication information in the response data packet to determine whether the charger and battery module are original equipment.

5. The electric bicycle safety control method based on NFC startup according to claim 4 is characterized in that: The authentication information in the response data packet includes a pre-stored device unique identification code and a handshake token generated in real time. The BMS determines whether the charger and battery module are original devices based on whether the device unique identification code and handshake token match the internal preset data.

6. The electric bicycle safety control method based on NFC startup according to claim 1 is characterized in that: When the BMS detects the connection status of the positive and negative electrodes of the battery module in real time, the detection circuit inside the BMS monitors the voltage polarity of the positive and negative electrodes of the battery module. When the voltage polarity does not match the preset correct polarity, the BMS controls the battery module to stop charging and discharging operations.

7. The electric bicycle safety control method based on NFC startup according to claim 6 is characterized in that: The voltage polarity detection circuit includes a high-voltage detection module and an MCU control unit. The high-voltage detection module monitors the positive and negative voltages of the battery module in real time, and sends them to the MCU control unit for polarity logic judgment after analog-to-digital conversion.

8. The electric bicycle safety control method based on NFC startup according to claim 1 is characterized in that: When the BMS detects the collision status of the positive and negative poles of the battery module in real time, the BMS uses the built-in short-circuit current detection circuit to monitor the transient current changes of the battery module in real time. When it detects that the sudden change of the transient current of the battery module exceeds the preset threshold, it determines that the positive and negative poles of the battery module have collided, and the BMS controls the battery module to stop charging and discharging.

9. The electric bicycle safety control method based on NFC startup according to claim 1 is characterized in that: When the main control MCU sends a start signal to the light switch module and the motor, the main control MCU outputs the start signal to the light switch module and the motor controller through the digital signal control circuit. The light switch module automatically lights up the lights after receiving the start signal, and the motor controller releases the motor lock state after receiving the start signal.

10. The electric bicycle safety control method based on NFC startup according to claim 1 is characterized in that: The data communication between the main control MCU and the instrument adopts a two-way handshake mechanism. After the instrument sends a start request to the main control MCU, the main control MCU returns a confirmation message to ensure that the start request is effectively received and prevent communication packet loss or erroneous operation. The confirmation information in the two-way handshake mechanism uses a check bit to check the integrity of the data packet. After the main control MCU sends the confirmation message, the instrument receives the confirmation message and verifies the check bit.

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